1. Field of the Invention
The present invention relates to a substrate for a semiconductor device, a semiconductor chip mounting substrate, a semiconductor device and method of fabrication thereof, and a circuit board, together with electronic equipment.
2. Description of Related Art
Methods have been developed for providing small packages such as chip scale/size packages (CSPs), which involve mounting a plurality of semiconductor chips on a flexible substrate then sealing the entire assembly in resin. The resultant sealed product is then cut into individual packages.
If the flexible substrate is cut by a blade or router in this case, a problem occurs in that the cutting generates dust at the corner portions of individual products, so a better solution is required.
To solve this problem, the present invention provides a substrate for a semiconductor device, a semiconductor chip mounting substrate, a semiconductor device and method of fabrication thereof, and a circuit board, together with electronic equipment comprising the same, wherein the generation of cutting dust is reduced.
(1) According to a first aspect of the present invention, there is provided a substrate for a semiconductor device, having a mounting region for a semiconductor chip, wherein at least one hole is formed at a position where cutting lines intersect.
The substrate for a semiconductor device in accordance with this invention can be cut apart to separate it into individual products that are semiconductor devices. The cutting is done along cutting lines. In practice, the cutting lines are of a striped form having a certain width. Corner portions of individual products are formed at positions where the cutting lines intersect.
With this aspect of the invention, xe2x80x9cholexe2x80x9d is not limited to a through hole; it can also refer to any other type of hole that does not penetrate, such as a depression. If a hole is formed at each position where cutting lines intersect, part of the substrate for the semiconductor device forms an indented shape at each corner portion of each individual product. If a depression is formed at each position where cutting lines intersect, part of the substrate for the semiconductor device is made thinner at each corner portion of each individual product.
Since parts of the substrate for the semiconductor device are either indented inward or is thinner at the corner portions of the individual products, it is therefore possible to reduce the amount of cutting dust when the cutting is done.
(2) In this substrate for a semiconductor device, one of the holes may be formed at the position where the cutting lines intersect; and the hole may be formed to a size that comprises an intersection portion of the cutting lines.
This ensures that the corner portions of individual products are defined by inner wall surfaces of the holes or thinner portions formed by the provision of the depressions. Part of the substrate for the semiconductor device is formed to be indented inward or thinner at each corner portion of each individual product.
(3) In this substrate for a semiconductor device, a plurality of the holes may be formed at the position where the cutting lines intersect; and part of each of the holes may be superimposed on an intersection portion between the cutting lines.
This ensures that the corner portions of individual products are defined by inner wall surfaces of the holes or thinner portions formed by the provision of the depressions. Part of the substrate for the semiconductor device can be formed to be indented inward or thinner at each corner portion of each individual product.
Moreover, since it is sufficient that part of each hole is superimposed on the intersection portion between the cutting lines, each hole can be made smaller.
(4) In this substrate for a semiconductor device, the plurality of holes may be positioned on edges of one of the cutting lines that is to be cut last, in the intersection portion.
(5) In this substrate for a semiconductor device, the plurality of holes may be formed on part of the cutting line that is to be cut last, when that part is to be cut earlier than the intersection portion between the cutting lines.
(6) In this substrate for a semiconductor device, the plurality of holes may be formed on part of the cutting line that is to be cut last, when that part is to be cut after the intersection portion between the cutting lines.
(7) In this substrate for a semiconductor device, the spacing between one of the holes formed on an edge of the cutting line that is to be cut last and another of the holes formed on another edge of the cutting line may be less than the thickness of a cutting portion of a cutting tool.
This configuration ensures that the cutting can be done to cut away a part of each hole and that the corner portions of individual products can be defined by inner wall surfaces of the holes or thinner portions formed by provision of the depressions.
(8) In this substrate for a semiconductor device, at least one of the holes may be formed; and the hole may have an aperture portion that is closed by a cover.
This makes it possible to prevent the sealing resin from flowing into the hole, and thus prevent the sealing resin from seeping from one surface of the semiconductor device to the other surface thereof through the hole.
(9) In this substrate for a semiconductor device, an interconnecting pattern may be formed; and the cover may be formed of the same material as the interconnecting pattern.
This makes it possible to form the cover without increasing the steps of the fabrication process.
(10) According to a second aspect of the present invention, there is provided a semiconductor chip mounting substrate, comprising: a substrate of a material that can be cut into separate pieces, in which is formed at least one hole at an intersection portion between cutting lines for separating the substrate into a plurality of individual products; and a plurality of semiconductor chips which are mounted on the substrate.
The substrate in accordance with this aspect of the invention, on which is mounted a plurality of semiconductor chips, can be cut apart to form a plurality of individual products. The cutting is done along the cutting lines. In practice, the cutting lines are of a striped form having a certain width. Corner portions of individual products of the substrate are formed at positions where the cutting lines intersect.
With this aspect of the invention, xe2x80x9cholexe2x80x9d is not limited to a through hole; it can also refer to any other type of hole that does not penetrate, such as a depression. If a hole is formed at each position where cutting lines intersect, each corner portion of each individual product of the substrate forms an indented shape. If a depression is formed at each position where cutting lines intersect, each corner portion of each individual product of the substrate is made thinner.
Since the corner portions of individual pieces of the substrate are either indented inward or are thinner, it is possible to reduce the amount of cutting dust even when the cutting is done along the intersecting cutting lines.
(11) In this semiconductor chip mounting substrate, the plurality of semiconductor chips may be sealed in by resin.
This configuration makes it possible to cut the resin apart simultaneously with the cutting of the substrate.
(12) In this semiconductor chip mounting substrate, the resin may fill the hole.
This provides resin in the intersection portion between cutting lines. If holes are formed in the substrate, each corner portion of the individual pieces of substrate and resin is formed by resin. If depressions are formed in the substrate, each corner portion of the individual pieces of substrate and resin is formed by a thinner piece of substrate and the resin.
(13) In this semiconductor chip mounting substrate, the hole may be formed to a size that comprises the intersection portion of the cutting lines.
(14) In this semiconductor chip mounting substrate, the hole may have an aperture portion that is closed by a cover, and the resin may be provided over a surface of the substrate for a semiconductor device where the cover is provided.
This makes it possible to prevent the resin from flowing into the hole and thus prevent seepage of the resin from one surface of the substrate to the other surface thereof through the hole.
(15) According to a third aspect of the present invention, there is provided a semiconductor device comprising:
a semiconductor chip;
a substrate on which the semiconductor chip is mounted and which is formed by cutting apart a larger substrate; and
resin for sealing the semiconductor chip;
wherein the semiconductor device has an outer shape having a corner portion; and
wherein a part of the substrate is indented further inward than an edge surface of the resin at the corner portion.
This aspect of the invention provides a configuration that reduces the amount of cutting dust that remains on the substrate after being generated at the corner portions by the cutting apart of the substrate.
(16) In this semiconductor device, the substrate at the corner portion may form a shape that is indented in the opposite direction from the direction in which the corner portion protrudes, and thus an edge surface of the substrate may be indented further inward than the edge surface of the resin.
(17) In this semiconductor device, the formation of a thinner portion in the substrate at the corner portion may ensure that a surface of the thinner portion of the substrate is indented further inward than the edge surface of the resin.
(18) In this semiconductor device, the part of the substrate that is indented further inward than the edge portion of the resin at the corner portion may be covered by the resin.
This ensures that part of the substrate is covered by resin at the corner portion so that no cutting dust is generated by the cutting apart of the substrate.
(19) In this semiconductor device, a cover may be provided at the corner portion, between the substrate and the resin; and the part of the substrate that is indented further inward than the edge surface of the resin may be exposed.
(20) According to a fourth aspect of the present invention, there is provided a circuit board which has any of the previously described semiconductor devices mounted thereon.
(21) According to a fifth aspect of the present invention, there is provided electronic equipment which is provided with any of the previously described semiconductor devices.
(22) According to a sixth aspect of the present invention, there is provided a method of fabricating a semiconductor device, the method comprising:
a first step of mounting a plurality of semiconductor chips on a substrate on which is formed at least one hole at a position where cutting lines intersect, then sealing the plurality of semiconductor chips with resin; and
a second step of cutting the substrate and the resin into individual products along the cutting lines, through at least part of the hole.
With this aspect of the invention, the substrate on which a plurality of semiconductor chips is mounted is cut apart to form a plurality of individual products. The cutting is done along cutting lines. In practice, the cutting lines are of a striped form having a certain width. Corner portions of individual pieces of the substrate and resin are formed at positions where the cutting lines intersect.
With this aspect of the invention, xe2x80x9cholexe2x80x9d is not limited to a through hole; it can also refer to any other type of hole that does not penetrate, such as a depression. If a hole is formed at each position where cutting lines intersect, part of the substrate for the semiconductor device forms an indented shape at each corner portion of each individual piece of the substrate and resin. If a depression is formed at each position where cutting lines intersect, part of the substrate for the semiconductor device is made thinner at each corner portion of each individual piece of the substrate and resin.
Since the part of the substrate is either indented inward or is thinner at each corner portion of each individual piece of the substrate and resin, it is possible to reduce the amount of cutting dust when the cutting is done along the intersecting cutting lines.
(23) In this method of fabricating a semiconductor device, the resin may fill the hole in the first step.
This ensures that resin is provided at the each intersection portion of the cutting lines. If holes are formed in the substrate, each corner portion of the individual pieces of the substrate and resin is formed by resin. If depressions are formed in the substrate, each corner portion of the individual pieces of the substrate and resin is formed by a thinner piece of the substrate and resin.
(24) In this method of fabricating a semiconductor device, at least one of the holes may be formed in the substrate; a cover may be provided to block the hole, before the first step; and flow of the resin into the hole during the first step may be prevented by the cover.
This makes it possible to prevent the resin from flowing into the hole and thus prevent seepage of the resin from one surface of the substrate to the other surface thereof through the hole.
(25) The method of fabricating a semiconductor device may further comprise a step of forming an interconnecting pattern in the substrate, before the first step, and the cover may be formed during the step of forming the interconnecting pattern.
This makes it possible to provide a cover without increasing the number of fabrication steps.
(26) In this method of fabricating a semiconductor device, one of the holes may be formed at the position where the cutting lines intersect; and the substrate and the resin may be cut through an inner side of the hole in the second step.
This makes it possible to define the corner portions of individual pieces of the substrate with inner wall surfaces of the holes or thinner portions formed by the provision of the depressions.
(27) In this method of fabricating a semiconductor device, a plurality of the holes may be formed at the position where the cutting lines intersect; the plurality of holes may be formed to be positioned on edges of one of the cutting lines that is to be cut last, at the position where the cutting lines intersect; and the substrate and the resin may be cut through part of the respective holes in the second step.
This makes it possible to define the corner portions of individual products of the substrate with inner wall surfaces of the holes or thinner portions formed by the provision of the depressions. Moreover, since it is sufficient that part of each hole is superimposed on the intersection portion between the cutting lines, each hole can be made smaller.
(28) In this method of fabricating a semiconductor device, the substrate and the resin may be cut by a cutting tool having a thickness that is greater than the spacing between one of the holes formed on an edge of the cutting line that is to be cut last and another of the holes formed on another edge of the cutting line.
This configuration ensures that the cutting is done to cut away part of each hole and that the corner portions of individual products of the substrate are defined with inner wall surfaces of the holes or thinner portions formed by provision of the depressions.